EXPERIMENT STATION BULLETINS. 271 



lime, adding water only as fast as it takes it up, and pour together. 

 Before using dilute to 40 gallons. Enough lime should be added to 

 neutralize the free acid, as, if this is not done, it will injure the foliage. 

 To test this, get five cents' worth of ferro-cyanide of potassium (yellow 

 prussiate of potash) at a drug store, and place in a small bottle of water. 

 Add a few drops of this solution to the Bordeaux mixture, before it is 

 diluted, and, if it turns it brown, the lime is deficient and more lime 

 should be added until the ferro-cyanide has no effect. In order to be sure 

 that a sufficient amount of lime has been used, a small quantity should be 

 added after the test shows a sufficiency. When much Bordeaux mixture 

 is used it is an excellent plan to make up a stock solution, which can be 

 diluted as used, proceeding as follows: Dissolve 40 pounds of copper sul- 

 phate in 40 gallons of water, and in a box slake 40 or 50 pounds of lime. 

 These can be kept as long as one desires. When needed, measure out 4 

 gallons of the copper sulphate solution and add some of the slaked lime 

 until no change in color can be produced by the test given above. The 

 mixture will then be ready for use when diluted. The strength of Bor- 

 deaux mixture can be varied to a considerable degree. The above formula 

 is about as strong as we care to use at any time, and, after the second 

 application, it is our custom to reduce it by using 50 and even 60 gallons 

 of water for the four pounds of copper sulphate and three of lime. This 

 can be done, with no apparent loss in the efficacy of the Bordeaux mixture, 

 when the fungi are not particularly troublesome, and when several appli- 

 cations are to be made at frequent intervals. If the lime is fresh and a 

 proper amourt is added after it has been carefully slaked, there is no 

 danger of burning the foliage with Bordeaux mixture. Another desirable 

 feature about this fungicide is that Paris green can be used with it, thus 

 saving one application, and that the lime also neutralizes any free arsen- 

 ious acid in the Paris green and greatly lessens it caustic effect. For all 

 fungous diseases of plants, such as mildews, rust, rots, and blights, in which 

 either the spores, or the body of the fungus itself, is exposed to its action. 

 Some recommend the addition of four pounds of molasses to the lime 

 after diluting it with water and before mixing with the copper sulphate. 

 This remains for a long time on the foliage and is considered very 

 effective. 



COPPER SULPHATE SOLUTION. 



(A) Copper sulphate 1 pound 8 



Water 25 gallons 



For use before the buds open, the above solution is easy to prepare and to 

 apply. It should not be applied to any plant after the leaves burst, as it 

 will barn the foliage. Its action is equal to Bordeaux mixture, but it does 

 not seem as lasting. • 



WEAK COPPER SULPHATE SOLUTIONS. 



(B) Copper sulphate 1 pound 



Water 250 gallons 



(C) Copper sulphate 1 pound 



Water 500 gallons 



